The Importance of Being PRECISE in Prostate Magnetic Resonance Imaging and Active Surveillance

The PRECISE Recommendations for Prostate MRI in Patients on Active Surveillance for Prostate Cancer: A Critical Review

The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations were published in 2016 to standardize the reporting of MRI examinations performed to assess for disease progression in patients on active surveillance for prostate cancer. Although a limited number of studies have reported outcomes from use of PRECISE in clinical practice, the available studies have demonstrated PRECISE to have high pooled NPV but low pooled PPV for predicting progression. Our experience in using PRECISE in clinical practice at two teaching hospitals has highlighted issues with its application and areas requiring clarification. This Clinical Perspective critically appraises PRECISE on the basis of this experience, focusing on the system's key advantages and disadvantages and exploring potential changes to improve the system's utility. These changes include consideration of image quality when applying PRECISE scoring, incorporation of quantitative thresholds for disease progression, adoption of a PRECISE 3F sub-category for progression not qualifying as substantial, and comparisons with both the baseline and most recent prior examinations. Items requiring clarification include derivation of a patient-level score in patients with multiple lesions, intended application of PRECISE score 5 (i.e., if requiring development of disease that is no longer organ-confined), and categorization of new lesions in patients with prior MRI-invisible disease.

mpMRI Interpretation in Active Surveillance for Prostate Cancer-An overview of the PRECISE score

Active surveillance (AS) is now included in all major guidelines for patients with low-risk PCa and selected patients with intermediate-risk PCa. Several studies have highlighted the potential benefit of multiparametric magnetic resonance imaging (mpMRI) in AS and it has been adopted in some guidelines. However, uncertainty remains about whether serial mpMRI can help to safely reduce the number of required repeat biopsies under AS. In 2017, the European School of Oncology initiated the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) panel which proposed the PRECISE scoring system to assess the likelihood of radiological tumor progression on serial mpMRI. The PRECISE scoring system remains the only major system evaluated in multiple publications. In this review article, we discuss the current body of literature investigating the application of PRECISE as it is not as yet an established standard in mpMRI reporting. We delineate the strengths of PRECISE and its potential added value. Also, we underline potential weaknesses of the PRECISE scoring system, which might be tackled in future versions to further increase its value in AS.

The role of multiparametric magnetic resonance in active surveillance of a low-risk prostate cancer cohort from clinical practice

INTRODUCTION

Active surveillance (AS) is considered a suitable management practice for those patients with low-risk prostate cancer (PCa). At present, however, the role of multiparametric magnetic resonance imaging (mpMRI) in AS protocols has not yet been clearly established.

OUTCOMES

To determine the role of mpMRI and its ability to detect significant prostate cancer (SigPCa) in PCa patients enrolled in AS protocols.

MATERIALS AND METHODS

There were 229 patients enrolled in an AS protocol between 2011 and 2020 at Reina Sofía University Hospital. MRI interpretation was based on PIRADS v.1 or v.2/2.1 classification. Demographics, clinical, and analytical data were collected and analyzed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for mpMRI in different scenarios. We defined SigPCa and reclassification/progression as a Gleason score (GS) ≥ 3 + 4, a clinical stage ≥T2b, or an increase in PCa volume. Kaplan-Meier and log-rank tests were used to estimate progression-free survival time.

RESULTS

Median age was 69.02 (±7.73) at diagnosis, with a 0.15 (±0.08) PSA density (PSAD). Eighty-six patients were reclassified after confirmatory biopsy, with a suspicious mpMRI an indication for a clear reclassification and risk-predictor factor in disease progression (p < 0.05). During follow-up, 46 patients were changed from AS to active treatment mainly due to disease progression. Ninety patients underwent ≥2mpMRI during follow-up, with a median follow-up of 29 (15-49) months. Thirty-four patients had a baseline suspicious mpMRI (at diagnostic or confirmatory biopsy): 14 patients with a PIRADS 3 and 20 patients with ≥PIRADS 4. From 14 patients with a PIRADS 3 baseline mpMRI, 29% progressed radiologically, with a 50% progression rate versus 10% (1/10 patients) for those with similar or decreased mpMRI risk. Of the 56 patients with a non-suspicious baseline mpMRI (PIRADS < 2), 14 patients (25%) had an increased degree of radiological suspicion, with a detection rate of SigPCa of 29%. The mpMRI NPV during follow-up was 0.91.

CONCLUSION

A suspicious mpMRI increases the reclassification and disease progression risk during follow-up and plays an important role in monitoring biopsies. In addition, a high NPV at mpMRI follow-up can help to decrease the need to monitor biopsies during AS.

Time series radiomics for the prediction of prostate cancer progression in patients on active surveillance

Serial MRI is an essential assessment tool in prostate cancer (PCa) patients enrolled on active surveillance (AS). However, it has only moderate sensitivity for predicting histopathological tumour progression at follow-up, which is in part due to the subjective nature of its clinical reporting and variation among centres and readers. In this study, we used a long short-term memory (LSTM) recurrent neural network (RNN) to develop a time series radiomics (TSR) predictive model that analysed longitudinal changes in tumour-derived radiomic features across 297 scans from 76 AS patients, 28 with histopathological PCa progression and 48 with stable disease. Using leave-one-out cross-validation (LOOCV), we found that an LSTM-based model combining TSR and serial PSA density (AUC 0.86 [95% CI: 0.78-0.94]) significantly outperformed a model combining conventional delta-radiomics and delta-PSA density (0.75 [0.64-0.87]; p = 0.048) and achieved comparable performance to expert-performed serial MRI analysis using the Prostate Cancer Radiologic Estimation of Change in Sequential Evaluation (PRECISE) scoring system (0.84 [0.76-0.93]; p = 0.710). The proposed TSR framework, therefore, offers a feasible quantitative tool for standardising serial MRI assessment in PCa AS. It also presents a novel methodological approach to serial image analysis that can be used to support clinical decision-making in multiple scenarios, from continuous disease monitoring to treatment response evaluation. KEY POINTS: •LSTM RNN can be used to predict the outcome of PCa AS using time series changes in tumour-derived radiomic features and PSA density. •Using all available TSR features and serial PSA density yields a significantly better predictive performance compared to using just two time points within the delta-radiomics framework. •The concept of TSR can be applied to other clinical scenarios involving serial imaging, setting out a new field in AI-driven radiology research.

Promoting the use of the PRECISE score for prostate MRI during active surveillance: results from the ESOR Nicholas Gourtsoyiannis teaching fellowship

Objectives

The PRECISE criteria for serial multiparametric magnetic resonance imaging (MRI) of the prostate during active surveillance recommend the use of a dedicated scoring system (PRECISE score) to assess the likelihood of clinically significant radiological change. This pilot study assesses the effect of an interactive teaching course on prostate MRI during active surveillance in assessing radiological change in serial imaging.

Methods

Eleven radiology fellows and registrars with different experience in prostate MRI reading participated in a dedicated teaching course where they initially evaluated radiological change (based on their previous training in prostate MRI reading) independently in fifteen patients on active surveillance (baseline and follow-up scan), and then attended a lecture on the PRECISE score. The initial scans were reviewed for teaching purposes and afterwards the participants re-assessed the degree of radiological change in a new set of images (from fifteen different patients) applying the PRECISE score. Receiver operating characteristic analysis was performed. Confirmatory biopsies and PRECISE scores given in consensus by two radiologists (involved in the original draft of the PRECISE score) were the reference standard.

Results

There was a significant improvement in the average area under the curve (AUC) for the assessment of radiological change from baseline (AUC: 0.60 [Confidence Intervals: 0.51–0.69] to post-teaching (AUC: 0.77 [0.70–0.84]). This was an improvement of 0.17 [0.016–0.28] (p = 0.004).

Conclusions

A dedicated teaching course on the use of the PRECISE score improves the accuracy in the assessment of radiological change in serial MRI of the prostate.

Magnetic Resonance Imaging–guided Active Surveillance of Prostate Cancer: Time to Say Goodbye to Protocol-based Biopsies

Traditional protocols for active surveillance (AS) are commonly based on digital rectal examination, prostate-specific antigen (PSA), and standard transrectal biopsy, meaning that initial classification errors and inaccurate lesion monitoring can occur. Protocol-based biopsies are performed to assess changes in cancer grade and extent at prespecified intervals, but this approach represents a barrier to AS adherence and tolerability. There is evidence to support the use of magnetic resonance imaging (MRI) during AS, as this technique (associated with favourable PSA kinetics) offers an opportunity to follow patients on AS without the need for routine, protocol-based biopsies in the absence of signs of radiological progression provided that image quality, interpretation, and reporting of serial imaging are of the highest standards.

Patient summary

In this report we looked at the role of magnetic resonance imaging (MRI) scans in avoiding unnecessary prostate biopsies for patients being monitored for low- or intermediate-risk prostate cancer. We conclude that patients on active surveillance can be monitored with MRI scans over time and that biopsies could be used only when there are changes on MRI or a rising prostate-specific antigen (PSA) not explained by an increase in prostate size.